McLaren look set to have to rely on their 2002 car for at least another two Grands Prix after deciding not to give their new car its debut this week.

The team had said they would test the definitive 2003 car, the MP4-18A, for the first time this week, but it is not ready, and McLaren would not confirm when it would take to the track for the first time.

A spokeswoman said there would be "a low-key launch of the car within the next month and the first test will follow shortly after that".

The new car is now likely to race for the first time at the Austrian Grand Prix on 18 May - but McLaren have said they will not race it until it is as reliable as the car they are using at the moment, the MP4-17D.

That is a revised version of their 2002 car, which has won all three of this year's Grands Prix - with Kimi Raikkonen provisionally winning two races and David Coulthard the other.